Nonspecific B and T cell-stimulatory activity mediated by mast cells is associated with exosomes

Int Arch Allergy Immunol. Jan-Mar 2001;124(1-3):133-6. doi: 10.1159/000053691.


Bone marrow-derived mouse mast cells (BMMC) and mast cell lines P815 and MC9 have recently been shown to induce antigen-independent B and T lymphocyte activation. It has been demonstrated that a physical contact between mast cells and B and T lymphocytes is not necessary since mast cell supernatants contain full activity. Electron microscopy studies revealed the presence in mast cell supernatants of small vesicles called exosomes with a heterogeneous size from 60 to 100 nm of diameter. When cocultured with spleen cells, purified exosomes induce B and T cell blast formation, proliferation as well as IL-2 and IFN-gamma production. In contrast to P815 and MC9 mast cell lines, a pretreatment with IL-4 is required for BMMC to produce active exosomes. Structurally, these exosomes were found to harbor immunologically relevant molecules such as MHC class II, CD86, LFA-1 and ICAM-1. Here we provide for the first time the evidence that mast cells use exosomes as sophisticated messengers to communicate with cells of the immune system.

MeSH terms

  • Animals
  • Antigens, CD / analysis
  • B-Lymphocytes / immunology*
  • B7-2 Antigen
  • Cells, Cultured
  • Cytokines / biosynthesis
  • Histocompatibility Antigens Class II / analysis
  • Intercellular Adhesion Molecule-1 / analysis
  • Lymphocyte Activation*
  • Lymphocyte Function-Associated Antigen-1 / analysis
  • Mast Cells / immunology*
  • Membrane Glycoproteins / analysis
  • Mice
  • Mice, Inbred DBA
  • Secretory Vesicles / chemistry
  • Secretory Vesicles / physiology*
  • T-Lymphocytes / immunology*


  • Antigens, CD
  • B7-2 Antigen
  • Cd86 protein, mouse
  • Cytokines
  • Histocompatibility Antigens Class II
  • Lymphocyte Function-Associated Antigen-1
  • Membrane Glycoproteins
  • Intercellular Adhesion Molecule-1